如何将数组分割成偶数长度块？

Question

我希望将数组拆分为偶数(或尽可能多的)块。函数的输入应该是数组和块的大小。假设你有数组

[1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17]

如果将其放入下面的函数中，以5作为块大小，则会产生以下结果

[[1,2,3,4,5],[6,7,8,9,10],[11,12,13,14,15],[16,17]

然而，我希望结果是

[[1,2,3,4,5],[6,7,8,9],[10,11,12,13],[14,15,16,17]

这意味着牺牲数组之前的长度，使它们只相差一个长度。

我目前使用的函数如下所述。我用模试过很多东西，但我搞不懂。

function chunkArray(myArray, chunkSize){
var arrayLength = myArray.length;
var tempArray = [];

for (index = 0; index < arrayLength; index += chunkSize) {
    myChunk = myArray.slice(index, index+chunkSize);
    // Do something if you want with the group
    tempArray.push(myChunk);
}

return tempArray;

}

Answer 1

使用此解决方案，您将得到均匀分割的数组项，直到最后一个项合并了所有遗留项(长度小于块大小的项的集合)。

​

const a = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17]
const chunk = 4

const chunk_array = (a, c) => {
  let arr = []
  
  a.forEach((_, i) => {
    if (i%chunk === 0) arr.push(a.slice(i, i+chunk))
  })
  
  const [left_overs] = arr.filter(a => a.length < chunk)
  
  arr = arr.filter(a => a.length >= chunk)
  
  arr[arr.length-1] = [...arr[arr.length-1], ...left_overs] 
  
  return arr
}

console.log(
  chunk_array(a, chunk)
)

​

Answer 2

如果数组长度是奇数，则可以使用模块进行检查：

let MY_CHUNK_CONST = 5
let first_chunk_size = MY_CHUNK_CONST,
other_chunk_size = MY_CHUNK_CONST;
let myArray = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17];
modulo_res = myArray.length % 2; // 0 if even 1 if odd

if(modulo_res){
 other_chunk_size = first_chunk_size - 1;
}

var tempArray = [];

myChunk = myArray.slice(0, 0+first_chunk_size);
tempArray.push(myChunk);
for (index = 1; index < myArray.length; index += other_chunk_size) {
    myChunk = myArray.slice(index, index+other_chunk_size);
    // Do something if you want with the group
    tempArray.push(myChunk);
}

console.log(tempArray)
// [[1,2,3,4,5],[6,7,8,9],[10,11,12,13],[14,15,16,17]

希望能帮上忙。

Answer 3

我的解决方案！

const chunk = (arr, chunkSize) => {
  let chunked = [];
  for (let i = 0; i< arr.length; i+=chunkSize){
    chunked.push(
      arr.slice(i, (i + chunkSize))
    );
  }

  return chunked;
};

const data = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17];

console.log(chunk(data, 5));
// returns [[1,2,3,4,5],[6,7,8,9,10],[11,12,13,14,15],[16,17]]